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Assessment of chronic pain states: MAP-ping out the terrain
IbL I No. 4 Fall 1986
Reviews
Journal of Pain and Symptom Management
235
Literature Review
Assessment of Chronic Pain States: MAP-ping Out the Terrain
Chronic Pain Slates: A Model For Classification By Steven E Brena Psychiatric Annals 1984;14;778-782.
Reviewed by Dennis C. Turk and T h o m a s E. Rudy Despite the growing awareness of the complexity of chronic pain and its assessment, there have been few attempts to integrate medical-physical and psychological data in the evaluation of chronic pain patients. Steven Brena and his colleagues (Stanley C h a p m a n and Daniel Koch) have been appealing for an integrative assessment approach for the past 15 years and toward that end they have developed a two-dimensional strategy that they labelled the Emory Pain Estimate Model. In the article under reviews;Brena describes the operationalization of the two dimensions that comprise the Emory model, describes the four classes of pain patients that are derived by dividing patient scores at the median on each of the two dimensions, and briefly notes some research on the psychometric properties of the Emory model. In an appendix to the article, Brena presents a description of the procedures employed to measure each of the two dimensions that he labels "pathology" and "behavior." The pathology dimension includes ratings of joint mobility and muscle strength, each based on quant-
Dennis C. Turk, PhD, is Professor of Psychiatry and Anesthesiology and Director of the Center for Pain Evaluation and Treatment, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania. Thomas E. Rud}; PhD, is Assistant Professor of Anesthesiology and Psychiatry and Associate Director of the Center for Pain Evaluation and Treatment, University of Pittsburgh School of Medicine.
ifying the results of physical examinations, as well as assigning numerical indices to reflect the a m o u n t of abnormalities resulting from diagnostic procedures such as radiographic studies. The behavioral dimension includes activity levels, pain verbalizations, drug use, and personality profiles based on the Minnesota Multiphasic Personality Inventory (MMPI). Although Brena has appropriately emphasized the importance of integrating physical and psychological assessment data, some of the basic characteristics of his procedure are problematic. First, from a conceptual and theoretical standpoint, the inclusion of activity levels, pain verbalizations, and personality profiles under a single dimension labelled "behavior" is tronbling. In fact these diverse areas might better be viewed as comprised of at least two factors, namely, behavior-functional and personality information. Next, neither of the dimensions incorporates psychosocial information likely to play an important role in chronic painJ For example, patients' appraisals of the impact of pain on various domains of their lives, levels of social support, and how that support relates to their ability to cope with chronic pain are not addressed. Examination of the scoring system employed in the Emory model highlights an additional problem in that it is based on an apriori weighting system and is presented as if it were based on equal interval scales. The justification for this level of m e a s u r e m e n t is questionable because most of the ratings, at least those based on clinical data, are ordinal ratings at best. Moreover, the weights assigned to specific medical-physical findings are arbitrary. Finally, applying median divisions to the two dimensions, while intuitively appealing, artificially creates four clusters of patients. That is, there is no statistical demonstration that four nonover-
236
Vol. I No. 4 Fall 1986
lapping groups o f pain patients "naturally exist" in these data. Visualization of the 2-by-2 grid presented by Brena a n d his colleagues in other related papers 2'3 reveals that extreme scores are treated the same as scores near the medians. This m e t h o d o f establishing a taxo n o m y o f pain may lead to erroneous or nonind e p e n d e n t patient classifications because it is derived from artificial a n d external criteria rather than from divisions or clusterings that occur naturally within patients' scores. In sum, Brena is conceptually correct and has been ahead of his time by advocating what appears to be now a generally accepted muhidim e n s i o n a l a p p r o a c h in the assessment o f chronic pain patients. However, the specific details o f the development and operationalization o f the Emory Pain Estimate Model are o p e n to question. At this time, what really seems needed is an extension of the model suggested by Brena and his colleagues. We propose that a muhiaxial assessment o f pain (MAP) integrating medical-physical findings with psychosocial and behavioral-functional data is required to more accurately assess chronic pain states. 4'1 In other words, as we conceptualize such a MAP, i t should consist o f at least three axes, physical, psychosocial, and functional. Axis I, the physical-medical axis, should include a quantifiable procedure to assess conventional medical findings. More specifically, this axis should consist o f a weighted system for scoring typical laboratory tests (eg, plain X-rays, electromyography) along with basic quantification o f physical examination procedures (eg, j o i n t . m o b i l i t y , gait and posture, muscular function). Axis II of the MAP, the psychosocial axis, should focus on patients' perceptions o f the impact o f pain on their lives, dysphoric mood, activity levels, and so forth. This axis would consist o f self-report instruments developed for and n o r m e d on pain patients. These assessment instruments should have psychometric p r o p e r t i e s c o n s i s t e n t with the s t a n d a r d s applied to other types o f widely used psychological tests. Ideall); they should not be excessively long or hard to complete, should require little or no clinician time, and should be able to be easily scored by a secretary (see, for example, the West-Haven Yale Muhidimensional Pain InventoryS). T h e third axis, behavioral-functional, should consist o f a set o f identified pain behaviors,
Reviews
Journal of Pain and Symptom Management
that is, obse~'able expressions o f pain and sufi fering, that should be readily evaluated by a wide variety of professional staff (eg, nurses, physical therapists, psychologists). Additionall); Axis III could contain measures of daily activity levels, medication usage, utilization o f heahh care services, and so forth. Tile specific contents o f the MAP system are not as important as ensuring that each axis is operationalized in a psychometrically sound m a n n e r . T h a t is, each test or p r o c e d u r e included should first o f all have had sufficient empirical work to demonstrate (a) ttle measurement system used is reliable and stable, (b) good construct validity has been established (ie, the scale truly measures what it was intended to measure), and (c) adequate studies to cross-vali. date the scale on multiple pain populations have been conducted. At the present time, psychosocial and behavioral-fimctional assessment methods a p p e a r to be closer to these goals than procedures used to measure the medical-physical axis. 6'4 This is likely due to the inherent difficulties o f quantifying a diversity o f clinical and laboratory findings as well as determining a set o f medical procedures that are relevant across multiple types of pain complaints. Additionall}; the clinical importance placed u p o n various medical-physical findings is probably variable across physicians, If the three axes we propose can, indeed, be established in ways that they are both clinically meaningful and psychometrically sound, sophisticated taxometrically-based statistical procedures such as cluster analyses and classification systems based on discriminant functions can be used to identify groups o f pain patients with c o m m o n sets o f characteristics a~cross these axes. T h e classifications, or to use Brena's" term "pain states" that evolve from these statistical methods may enhance our understanding of pain, contribute to m o r e equitable decisions regarding disability assist in evaluation and the prescription o f specific therapeutic interventions, and further o u r ability to predict treatment outcome. In sum, Brena makes a cogent case for the need to integrate diverse physical and psychological data in evaluating chronic pain states. T h e limitations we identified for the Emory Pain Estimate Model in no way diminish Brena's seminal contribution to assessment o f chronic pain. He has pointed the direction and now it is time to "MAP" out the terrain.
Vol. I No. 4 Fall 1986
References 1. Turk DC, Rudy TE, Boucek, CD. T h e contribution o f psychological factors to the e x p e r i e n c e o f chronic pain. In: Warfield CA, ed. T h e anesthesiologist's guide to pain management. Hingham, MA: Kluwer Academic Publishers, in press. 2. Brena SF, Koch DL. A "Pain Estimate" model for quantification and classification o f chronic pain states. Anesthesiology Review 1975;2:8-13. 3. Brena SF, Chapman, SL. Chronic pain: an algorithm for nmnagement.-Postgraduate Medicine 1982;72:111-117. 4. Turk RD, Rudy TE. Assessment of cognitive factors in cltronic pain: a worthwhile enterprise? J Consuh Clin Psychol, in press. 5. Kerns RD, Turk DC, Rudy TE. T h e West HavenYale m u l t i d i m e n s i o n a l p a i n inventory. Pain 1985;23:345-356. 6. Keefe FJ, Gil KM. Behavioral concepts in the analysis of chronic pain syndromes.J Consult Clin l'sychol, in press.
Books Received
Andreasen NC. The Broken Brain: The Biological Revolution in Psychiatry. New York: Harper & Rm~, 1984, 278 pages. Aronoff, GM, ed. Evaluation and Treatment of Chronic Pain. Baltimore-Munich: Urban & Schwarzenberg. 1986, 684 /mges. Barlm~, Dtt, ed. Clinical tlandbook of Psk'chologicalDisorders. New York: Guilford Press, 1985, 186 pages. BillingsJA. Outpatient Management of Advanced Cancer:Symptom Control, Support, arut tIospice-in.the-Home. Philadelphia: Lippincott, 1985, 340 pages. Blanchard EB, Andrasik E Management of Chronic Headaches: A PsychologicalApproach. New York: Pergamon Press, 1985, 202 pages. Bonica .1], Ventafridda V, Pagnir CA, eds. Management of Superior Pulmonary Sulcns Sylutrome (Pancoast Syndrome) (Advaru:es in Pain Research alut Therapy, Vol 4). New York: Raven Press, 1982, 242 pages. Crasilneck HB, ttall JA. Clinical ll)IJnosis: Principles arut Applications. Orlando, FL: Grune & Stratton, 1985, 486 pages.
Reviews
Journal of l'ain and Symptom Management
23 7
Ehon D, Stanley G, Burrows G. PsychologicalControl of Pain. New York: Grune & Stratton, 1983, 354 pages. Fields, IlL, Dubner R, Cervero F, eds. Proceedings of the Fourth llbrld Congress on Pain, Seattle (Advances in Pain Research and Therapy, Vol 9). New York, Raven Press, 1985, 923 pages. Foley KM, Inturrisi CE, eds. Opioid Analgesics in the Management of Clin#al Pain (Advances in Pain Research and Therap); Ibl 8). New York: Raven Press, 1985, 466 pages. Graber, GC, Beasley AD, EaddyJA. Ethical Analysis of Clini. eal Medicine: A Guide to SelfEvaluation. Bahimore-Munich: Urban & Schwarzenberg, 1985, 302 pages. ttavens LL. Making Contact: Uses of Language in Psychother. ap): Cambridge, MA; Harvard University Press, 1986, 201 pages. ttersen M, ed. Pharmacological and Behavioral Treatment:An Integrative Approach. New York: Wiley-Interscience, 1986, 400 pages. ttess, H, ed. Pharmaceutical Dosage Forms and Their Use. Berne: ttans ttuber, 1985, 82 pages. Holzman AD, Turk DC, eds. Pain Management:A tIandbook of Psychological Treatment Approaches. New York: Pergamon Press, 1986, 287 pages. Kunze M, Wood, M, eds. Guidelines on Smoking Cessation (UICC Technical Report Series, lbl 79). Berne: Hans Huber, 1984, 74 pages. Leavitt SR. The Chronic Pain Patient: Theory, Evaluation and Treatment, Chapel Hill, NC: Pain Resource Center, 1983, 7 at, diocassettes including manual. Seltzer LE Paradoxical Strategies in Psychotherapy:A Compre. hensive Overview and Guidebook. New York: Wile), 1986, 323 pages. Spengler DM, Low Back Pain: Assessment and Management. New York: Grune & Stratton, 1982. 160 pages. Taylor SE. Itealth Psychology. New York: Random House, 1986. 528 pages. Temoshok L, Van Dyke C, Zegans LS, eds. Emotions in IIealth and Illness: Theoretical and Research Foundations. Orlando, FL: Grune & Stratton, 1983, 271 pages. Van Dyke C, Temoshok L, Zegans LS, eds. Emotions in Itealth and Illness: Applications to Clinical Practice. Orlando, FL: Grune & Stratton, 1984, 278 pages. Velleman PF, Hoaglin DC. Applications, Basics, and Computing of Exploratory Data Anal)'sis. Boston: Duxbury Press, 1981. 254 pages. Weisman, AD. The Coping Capacity: OI, the Nature of Being Mortal. New York: Human Sciences Press, 1984, 165 pages. White L, Tursky B, Schwartz GE, eds. Placebo: Theory, Research and Mechanisms. New York: Guilford Press, 1985, 474 pages. Zimmerman,JM. ttospice: Complete Carefor the Terminally Ill (2nd edition). Baltimore-Munich: Urban & Schwarzenberg, 1986, 311 pages.
Reviews
Journal of Pain and Symptom Management
235
Literature Review
Assessment of Chronic Pain States: MAP-ping Out the Terrain
Chronic Pain Slates: A Model For Classification By Steven E Brena Psychiatric Annals 1984;14;778-782.
Reviewed by Dennis C. Turk and T h o m a s E. Rudy Despite the growing awareness of the complexity of chronic pain and its assessment, there have been few attempts to integrate medical-physical and psychological data in the evaluation of chronic pain patients. Steven Brena and his colleagues (Stanley C h a p m a n and Daniel Koch) have been appealing for an integrative assessment approach for the past 15 years and toward that end they have developed a two-dimensional strategy that they labelled the Emory Pain Estimate Model. In the article under reviews;Brena describes the operationalization of the two dimensions that comprise the Emory model, describes the four classes of pain patients that are derived by dividing patient scores at the median on each of the two dimensions, and briefly notes some research on the psychometric properties of the Emory model. In an appendix to the article, Brena presents a description of the procedures employed to measure each of the two dimensions that he labels "pathology" and "behavior." The pathology dimension includes ratings of joint mobility and muscle strength, each based on quant-
Dennis C. Turk, PhD, is Professor of Psychiatry and Anesthesiology and Director of the Center for Pain Evaluation and Treatment, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania. Thomas E. Rud}; PhD, is Assistant Professor of Anesthesiology and Psychiatry and Associate Director of the Center for Pain Evaluation and Treatment, University of Pittsburgh School of Medicine.
ifying the results of physical examinations, as well as assigning numerical indices to reflect the a m o u n t of abnormalities resulting from diagnostic procedures such as radiographic studies. The behavioral dimension includes activity levels, pain verbalizations, drug use, and personality profiles based on the Minnesota Multiphasic Personality Inventory (MMPI). Although Brena has appropriately emphasized the importance of integrating physical and psychological assessment data, some of the basic characteristics of his procedure are problematic. First, from a conceptual and theoretical standpoint, the inclusion of activity levels, pain verbalizations, and personality profiles under a single dimension labelled "behavior" is tronbling. In fact these diverse areas might better be viewed as comprised of at least two factors, namely, behavior-functional and personality information. Next, neither of the dimensions incorporates psychosocial information likely to play an important role in chronic painJ For example, patients' appraisals of the impact of pain on various domains of their lives, levels of social support, and how that support relates to their ability to cope with chronic pain are not addressed. Examination of the scoring system employed in the Emory model highlights an additional problem in that it is based on an apriori weighting system and is presented as if it were based on equal interval scales. The justification for this level of m e a s u r e m e n t is questionable because most of the ratings, at least those based on clinical data, are ordinal ratings at best. Moreover, the weights assigned to specific medical-physical findings are arbitrary. Finally, applying median divisions to the two dimensions, while intuitively appealing, artificially creates four clusters of patients. That is, there is no statistical demonstration that four nonover-
236
Vol. I No. 4 Fall 1986
lapping groups o f pain patients "naturally exist" in these data. Visualization of the 2-by-2 grid presented by Brena a n d his colleagues in other related papers 2'3 reveals that extreme scores are treated the same as scores near the medians. This m e t h o d o f establishing a taxo n o m y o f pain may lead to erroneous or nonind e p e n d e n t patient classifications because it is derived from artificial a n d external criteria rather than from divisions or clusterings that occur naturally within patients' scores. In sum, Brena is conceptually correct and has been ahead of his time by advocating what appears to be now a generally accepted muhidim e n s i o n a l a p p r o a c h in the assessment o f chronic pain patients. However, the specific details o f the development and operationalization o f the Emory Pain Estimate Model are o p e n to question. At this time, what really seems needed is an extension of the model suggested by Brena and his colleagues. We propose that a muhiaxial assessment o f pain (MAP) integrating medical-physical findings with psychosocial and behavioral-functional data is required to more accurately assess chronic pain states. 4'1 In other words, as we conceptualize such a MAP, i t should consist o f at least three axes, physical, psychosocial, and functional. Axis I, the physical-medical axis, should include a quantifiable procedure to assess conventional medical findings. More specifically, this axis should consist o f a weighted system for scoring typical laboratory tests (eg, plain X-rays, electromyography) along with basic quantification o f physical examination procedures (eg, j o i n t . m o b i l i t y , gait and posture, muscular function). Axis II of the MAP, the psychosocial axis, should focus on patients' perceptions o f the impact o f pain on their lives, dysphoric mood, activity levels, and so forth. This axis would consist o f self-report instruments developed for and n o r m e d on pain patients. These assessment instruments should have psychometric p r o p e r t i e s c o n s i s t e n t with the s t a n d a r d s applied to other types o f widely used psychological tests. Ideall); they should not be excessively long or hard to complete, should require little or no clinician time, and should be able to be easily scored by a secretary (see, for example, the West-Haven Yale Muhidimensional Pain InventoryS). T h e third axis, behavioral-functional, should consist o f a set o f identified pain behaviors,
Reviews
Journal of Pain and Symptom Management
that is, obse~'able expressions o f pain and sufi fering, that should be readily evaluated by a wide variety of professional staff (eg, nurses, physical therapists, psychologists). Additionall); Axis III could contain measures of daily activity levels, medication usage, utilization o f heahh care services, and so forth. Tile specific contents o f the MAP system are not as important as ensuring that each axis is operationalized in a psychometrically sound m a n n e r . T h a t is, each test or p r o c e d u r e included should first o f all have had sufficient empirical work to demonstrate (a) ttle measurement system used is reliable and stable, (b) good construct validity has been established (ie, the scale truly measures what it was intended to measure), and (c) adequate studies to cross-vali. date the scale on multiple pain populations have been conducted. At the present time, psychosocial and behavioral-fimctional assessment methods a p p e a r to be closer to these goals than procedures used to measure the medical-physical axis. 6'4 This is likely due to the inherent difficulties o f quantifying a diversity o f clinical and laboratory findings as well as determining a set o f medical procedures that are relevant across multiple types of pain complaints. Additionall}; the clinical importance placed u p o n various medical-physical findings is probably variable across physicians, If the three axes we propose can, indeed, be established in ways that they are both clinically meaningful and psychometrically sound, sophisticated taxometrically-based statistical procedures such as cluster analyses and classification systems based on discriminant functions can be used to identify groups o f pain patients with c o m m o n sets o f characteristics a~cross these axes. T h e classifications, or to use Brena's" term "pain states" that evolve from these statistical methods may enhance our understanding of pain, contribute to m o r e equitable decisions regarding disability assist in evaluation and the prescription o f specific therapeutic interventions, and further o u r ability to predict treatment outcome. In sum, Brena makes a cogent case for the need to integrate diverse physical and psychological data in evaluating chronic pain states. T h e limitations we identified for the Emory Pain Estimate Model in no way diminish Brena's seminal contribution to assessment o f chronic pain. He has pointed the direction and now it is time to "MAP" out the terrain.
Vol. I No. 4 Fall 1986
References 1. Turk DC, Rudy TE, Boucek, CD. T h e contribution o f psychological factors to the e x p e r i e n c e o f chronic pain. In: Warfield CA, ed. T h e anesthesiologist's guide to pain management. Hingham, MA: Kluwer Academic Publishers, in press. 2. Brena SF, Koch DL. A "Pain Estimate" model for quantification and classification o f chronic pain states. Anesthesiology Review 1975;2:8-13. 3. Brena SF, Chapman, SL. Chronic pain: an algorithm for nmnagement.-Postgraduate Medicine 1982;72:111-117. 4. Turk RD, Rudy TE. Assessment of cognitive factors in cltronic pain: a worthwhile enterprise? J Consuh Clin Psychol, in press. 5. Kerns RD, Turk DC, Rudy TE. T h e West HavenYale m u l t i d i m e n s i o n a l p a i n inventory. Pain 1985;23:345-356. 6. Keefe FJ, Gil KM. Behavioral concepts in the analysis of chronic pain syndromes.J Consult Clin l'sychol, in press.
Books Received
Andreasen NC. The Broken Brain: The Biological Revolution in Psychiatry. New York: Harper & Rm~, 1984, 278 pages. Aronoff, GM, ed. Evaluation and Treatment of Chronic Pain. Baltimore-Munich: Urban & Schwarzenberg. 1986, 684 /mges. Barlm~, Dtt, ed. Clinical tlandbook of Psk'chologicalDisorders. New York: Guilford Press, 1985, 186 pages. BillingsJA. Outpatient Management of Advanced Cancer:Symptom Control, Support, arut tIospice-in.the-Home. Philadelphia: Lippincott, 1985, 340 pages. Blanchard EB, Andrasik E Management of Chronic Headaches: A PsychologicalApproach. New York: Pergamon Press, 1985, 202 pages. Bonica .1], Ventafridda V, Pagnir CA, eds. Management of Superior Pulmonary Sulcns Sylutrome (Pancoast Syndrome) (Advaru:es in Pain Research alut Therapy, Vol 4). New York: Raven Press, 1982, 242 pages. Crasilneck HB, ttall JA. Clinical ll)IJnosis: Principles arut Applications. Orlando, FL: Grune & Stratton, 1985, 486 pages.
Reviews
Journal of l'ain and Symptom Management
23 7
Ehon D, Stanley G, Burrows G. PsychologicalControl of Pain. New York: Grune & Stratton, 1983, 354 pages. Fields, IlL, Dubner R, Cervero F, eds. Proceedings of the Fourth llbrld Congress on Pain, Seattle (Advances in Pain Research and Therapy, Vol 9). New York, Raven Press, 1985, 923 pages. Foley KM, Inturrisi CE, eds. Opioid Analgesics in the Management of Clin#al Pain (Advances in Pain Research and Therap); Ibl 8). New York: Raven Press, 1985, 466 pages. Graber, GC, Beasley AD, EaddyJA. Ethical Analysis of Clini. eal Medicine: A Guide to SelfEvaluation. Bahimore-Munich: Urban & Schwarzenberg, 1985, 302 pages. ttavens LL. Making Contact: Uses of Language in Psychother. ap): Cambridge, MA; Harvard University Press, 1986, 201 pages. ttersen M, ed. Pharmacological and Behavioral Treatment:An Integrative Approach. New York: Wiley-Interscience, 1986, 400 pages. ttess, H, ed. Pharmaceutical Dosage Forms and Their Use. Berne: ttans ttuber, 1985, 82 pages. Holzman AD, Turk DC, eds. Pain Management:A tIandbook of Psychological Treatment Approaches. New York: Pergamon Press, 1986, 287 pages. Kunze M, Wood, M, eds. Guidelines on Smoking Cessation (UICC Technical Report Series, lbl 79). Berne: Hans Huber, 1984, 74 pages. Leavitt SR. The Chronic Pain Patient: Theory, Evaluation and Treatment, Chapel Hill, NC: Pain Resource Center, 1983, 7 at, diocassettes including manual. Seltzer LE Paradoxical Strategies in Psychotherapy:A Compre. hensive Overview and Guidebook. New York: Wile), 1986, 323 pages. Spengler DM, Low Back Pain: Assessment and Management. New York: Grune & Stratton, 1982. 160 pages. Taylor SE. Itealth Psychology. New York: Random House, 1986. 528 pages. Temoshok L, Van Dyke C, Zegans LS, eds. Emotions in IIealth and Illness: Theoretical and Research Foundations. Orlando, FL: Grune & Stratton, 1983, 271 pages. Van Dyke C, Temoshok L, Zegans LS, eds. Emotions in Itealth and Illness: Applications to Clinical Practice. Orlando, FL: Grune & Stratton, 1984, 278 pages. Velleman PF, Hoaglin DC. Applications, Basics, and Computing of Exploratory Data Anal)'sis. Boston: Duxbury Press, 1981. 254 pages. Weisman, AD. The Coping Capacity: OI, the Nature of Being Mortal. New York: Human Sciences Press, 1984, 165 pages. White L, Tursky B, Schwartz GE, eds. Placebo: Theory, Research and Mechanisms. New York: Guilford Press, 1985, 474 pages. Zimmerman,JM. ttospice: Complete Carefor the Terminally Ill (2nd edition). Baltimore-Munich: Urban & Schwarzenberg, 1986, 311 pages.